Polarization-Independent Circulator Based on Composite Rod of Ferrite and Plasma in Photonic Crystal Structure.

Mi Lin,Shakeel Ahmed,Zhengbiao Ouyang,Qiong Wang,Zixian Liang,Lixin Fu,Yaoxian Zheng

doi:10.3390/nano11020381

Abstract

We propose a type of polarization-independent circulator based on a composite rod of ferrite and plasma materials in a two-dimensional photonic crystal (PhC) slab. Only one composite rod was set at the center of the structure to provide circulation for both TE- and TM-polarized waves. Additionally, to improve the performance of the circulator, three additional rods were inserted to improve the coupling condition between the center magneto-optical microcavity and the corresponding waveguides. Finite element method was used to calculate the characteristics of the structure and the Nelder–Mead optimization method was employed to obtain the optimum parameters. The results show that a low insertion loss (~0.22 dB) and high isolation (~14 dB) can be achieved in our structure for waves of both TE and TM polarizations. The idea presented here may be useful for designing compact polarization devices in large-scale integrated photonic circuits.

Highlights

In our previous work [22], we proved that the ferrite material can provide a rotation effect for TE polarization, while the plasma material can provide a rotation effect for TM
We have proposed and demonstrated a type of polarization-independent circulators (PICs) based on a composite rod containing ferrite and plasma materials in a 2D photonic crystal (PhC) slab
Three additional rods are introduced into the waveguides in our optimized model to improve the coupling condition between the center MO cavity and the waveguides

Summary

Introduction

Coupled mode theory was applied in their designs, and high isolation and transmission circulators were successfully built by coupling an MO cavity and waveguides at optical frequencies. Their designs can be used in TM polarization. A very low splitting factor was used in their design, making their circulators feasible for the microwave or terahertz region Nanomaterials 2021, 11, 381 used in their design, making their circulators feasible for the microwave or terahertz region

The structure is based on triana 2D gular-lattice

Numerical Results and Discussion

Conclusions